490 Chapter XV 



Lustig and Galeotti^ have described another method of preparing 

 antiplague vaccine which can be utilised where it is of importance to 

 obtain a large quantity of vaccine in a very short time. Instead of 

 allowing the cultures to grow for five or six weeks as required by 

 HafiTdne's method, the Italian observers make use of cultures on agar 

 which have grown for two days only. The micro-organisms, removed 

 from the surface of the agar, are treated with a weak solution of 

 potash (0*75 7o — 1 °/o) which dissolves the bodies of the coccobacillL 

 [513] This phenomenon has sometimes occurred by the end of twenty 

 minutes, but it often requires an hour or more. The contact of the 

 micro-organisms with the alkali must never exceed three hours. 

 The viscous mass thus obtained is then treated with acetic acid, when 

 a precipitate is thrown down. This precipitate, after being washed, is 

 used for the vaccinations. When injected in large quantities into 

 animals, Lustig and Galeotti's product sets up necrosis, but a weak 

 dose is well borne and confers immunity against plague. In man it 

 is sufficient to inject two or three milligrammes of this substance 

 diluted with water. The vaccinal nuclein of the Italian observers has 

 been but little employed for the immunisation of man in India, but 

 it is largely used in this country for the inoculation of horses from 

 which to obtain an antiplague serum. 



The serotherapeutics against human plague were inaugurated by 

 the researches of Yersin, Borrel, and Calmette (l.c), who demon- 

 strated that animals susceptible to the plague bacillus can be 

 vaccinated and even cured of experimental plague. The preparation 

 of antiplague serum has since been energetically pursued under 

 Roux's direction at the Pasteur Institute. After several trials, 

 some of which were very encouraging, others, on the contrary, 

 somewhat unfavourable, they succeeded in obtaining a serum which 

 is capable of curing plague after it has broken out and has become 

 grave. As in this treatise we intentionally leave aside everything 

 connected with healing we shall speak only of the antiplague serum 

 as a protective agent. 



Whilst vaccinations by killed plague cultures have been practised 

 principally in the East Indies, the immunisation with antiplague serum 

 has been employed in Europe, especially at the time of the epidemics 

 of Oporto in 1899 and of Glasgow in 1900. In all these cases use was 

 made of the serum from the Pasteur Institute, up to the present the 

 most active of all those prepared. It is a serum obtained from 

 1 Deutsche med. Wchnschr., Leipzig, 1897, SS. 227, 289- 



